scholarly journals Reply to the Effect of Vigorous Physical Activity and Body Composition on Cortical Bone Mass in Adolescence

2015 ◽  
Vol 30 (3) ◽  
pp. 585-586
Author(s):  
Vina PS Tan ◽  
Heather M Macdonald ◽  
Heather A McKay
Keyword(s):  
Physical Activity ◽  
Body Composition ◽  
Bone Mass ◽  
Cortical Bone ◽  
Vigorous Physical Activity ◽  
Cortical Bone Mass

scholarly journals Influence of a School-based Physical Activity Intervention on Cortical Bone Mass Distribution: A 7-year Intervention Study

2016 ◽  
Vol 99 (5) ◽  
pp. 443-453 ◽  
Author(s):  
Jesper Fritz ◽  
Rachel L. Duckham ◽  
Timo Rantalainen ◽  
Björn E. Rosengren ◽  
Magnus K. Karlsson ◽  
...  
Keyword(s):  
Physical Activity ◽  
Bone Mass ◽  
Cortical Bone ◽  
Mass Distribution ◽  
Intervention Study ◽  
Physical Activity Intervention ◽  
School Based ◽  
Cortical Bone Mass

scholarly journals Physical activity, sedentary time and bone tissue: effects of an 8-months interdisciplinary program with overweight/obese children

2019 ◽  
Vol 23 ◽  
pp. 1-7
Author(s):  
Júlio Brugnara Mello ◽  
Luís Filipe Gomes Barbosa Pereira de Lemos ◽  
Luísa Maria Aires ◽  
Gustavo Silva ◽  
Rafael Miranda Tassitano ◽  
...  
Keyword(s):  
Physical Activity ◽  
Bone Mineral Density ◽  
Body Composition ◽  
Bone Mass ◽  
Bone Tissue ◽  
Bone Mineral ◽  
Sedentary Time ◽  
Vigorous Physical Activity ◽  
Z Score ◽  
Mineral Density

Moderate to vigorous physical activity plays a recognized osteogenic effect on bone. Moreover, sedentary time, and fat accumulation are unfavorable to bone health. Our study aimed (1) to examine changes in body composition, bone tissue, physical activity, and sedentary time; and (2) to explore whether changes in physical activity intensities and in sedentary time are associated with changes in bone outcomes after a school-based interdisciplinary intervention program. A total of 53 overweight/obese students (10.6 ± 3.5 year-olds; 26 girls) participated in physical activity classes. Bone area, bone mass, and bone mineral density z-score, body composition (fat mass, fat lean mass), physical activity, sedentary time and potential confounders (vitamin D and maturational status) were assessed at baseline, and 8 months later. General Linear Models were carried out and significance level was set at 5%. Changes in moderate to vigorous physical activity were positively correlated with changes in all bone mass indicators. We observed a significant overall effect of the intervention on bone mineral density z-score changes, however after adjustments for changes in sedentary time and moderate to vigorous physical activity, no effect was observed. Finally, variations in sedentary time and in moderate to vigorous physical activity play an important role in bone mass density in those participants of the interdisciplinary program.

scholarly journals The myokine irisin increases cortical bone mass

2015 ◽  
Vol 112 (39) ◽  
pp. 12157-12162 ◽  
Author(s):  
Graziana Colaianni ◽  
Concetta Cuscito ◽  
Teresa Mongelli ◽  
Paolo Pignataro ◽  
Cinzia Buccoliero ◽  
...  
Keyword(s):  
Physical Activity ◽  
Adipose Tissue ◽  
Bone Mass ◽  
Cortical Bone ◽  
Low Dose ◽  
Bending Strength ◽  
Molecular Entity ◽  
Weekly Dose ◽  
Mineral Density ◽  
Cortical Bone Mass

It is unclear how physical activity stimulates new bone synthesis. We explored whether irisin, a newly discovered myokine released upon physical activity, displays anabolic actions on the skeleton. Young male mice were injected with vehicle or recombinant irisin (r-irisin) at a low cumulative weekly dose of 100 µg kg−1. We observed significant increases in cortical bone mass and strength, notably in cortical tissue mineral density, periosteal circumference, polar moment of inertia, and bending strength. This anabolic action was mediated primarily through the stimulation of bone formation, but with parallel notable reductions in osteoclast numbers. The trabecular compartment of the same bones was spared, as were vertebrae from the same mice. Higher irisin doses (3,500 µg kg−1 per week) cause browning of adipose tissue; this was not seen with low-dose r-irisin. Expectedly, low-dose r-irisin modulated the skeletal genes, Opn and Sost, but not Ucp1 or Pparγ expression in white adipose tissue. In bone marrow stromal cell cultures, r-irisin rapidly phosphorylated Erk, and up-regulated Atf4, Runx2, Osx, Lrp5, β-catenin, Alp, and Col1a1; this is consistent with a direct receptor-mediated action to stimulate osteogenesis. We also noted that, although the irisin precursor Fndc5 was expressed abundantly in skeletal muscle, other sites, such as bone and brain, also expressed Fndc5, albeit at low levels. Furthermore, muscle fibers from r-irisin–injected mice displayed enhanced Fndc5 positivity, and irisin induced Fdnc5 mRNA expression in cultured myoblasts. Our data therefore highlight a previously unknown action of the myokine irisin, which may be the molecular entity responsible for muscle–bone connectivity.

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